Tubing anchor



Oct. 22, 1968 J. s. PAGE, JR 3,406,753

TUBING ANCHOR l Filed May 2l, 1965 5 Sheets-Sheet 1 INVENTOR.

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TUBING ANCHOR Oct. 22, 1968 Filed May 21, 1965 Oct. 22, 1968 .1.5. PAGE, JR 3,406,758

TUBING ANCHOR Filed May 2l, 1965 5 Sheets-Sheet 5 6 INVENTOR.

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United States Patent O lice ABSTRACT OF THE DISCLOSURE The disclosure concerns a well tubing anchor assembly in which release of slip connection to the well bore is effected in response to upward tensioning of the string folf lowed by sudden release of such tensioning afforded by uncoupling of a mandrel from anchor structure in the well.

This application is a continuation-in-part of my copending application entitled, fTubing Anchor, Ser. No. 434, 274, led Feb. 23, 1965, no w abandoned.

This invention relates generally to anchoring of tubing in wells, and more specifically concerns apparatus and s method to achieve anchoring and release of tubing from well casing in such manner as to overcome certain problems that are encountered with conventional anchoring equipment.

The general purpose of tubing anchoring equipment is to hold the tubing against vertical displacement in response to vertical stroking of pumping equipment. If the tubing is not so held, the effective stroke of the well pump is diminished, and as a result the production of well lluid is less than that which occurs if the tubing is effectively anchored. Actual installation of such equipment is made difficult by the necessity for special landing apparatus necessary to obtain tension setting; also, operation of such equipment is hampered by virtue of the occurrence of tem perature induced lengthwise expansion and contraction of the tubing relative to the casing, elevated temperature of the petroleum'for example tending to heat the tubing. In this regard, if the tubing is anchored deep in the hole when expanded at high temperature, subsequent cooling and lengthwise contraction ofthe anchored tubing may result in excessive tension -build-up. Further, release of conventional tubing anchors requires special landing equipment necessary to effect lowering of the anchor relative to the tubing.

It is a major object of the present invention to overcome these and other difficulties with conventional tubing anchoring equipment. Broadly considered in overall combination with a well tubing string, the equipment includes slip structure carried by the string for connecting to a well bore, and fluid pressure responsive actuator means movable downwardly on the string to actuate the slips to connect to the well bore, and movable upwardly to release the slips. In addition, other means may be provided to be responsive to sudden release of strain energy stored in the string to lift the actuator and thereby induce disconnection of the slip structure from the Well bore. More specifically, a typical tubular anchor assembly includes tubular body means (inclusive for example of a mandrel) connectible in upright series relation with a tubing string for passing well fluid; a second means including slip structure and an actuator carried by the tubular means, the actuator having capacity for vertical movement relative to said tubular means and having a piston surface communicablewith the interior of said tubular means to receive application of well Huid pressure for urging the actuator downwardly 3,406,758 Patented Oct. 22, v1968 thereby displacing the slip structure toward the well casing in order to anchor the string against upward movement relative to the casing; and other means for transmitting between the tubular means and slip structure string loading exerted axially upwardly, the tubular means and other means including a coupling for blocking relative vertical displacement of the tubular means and slip structure and for unblocking said relative vertical displacement upon coupling releasing loading application to the tubular means, upward displacement of the tubularymeans relative to the slip structure then being operable to urge the actuator upwardly thereby to free said slip structure for disconnection from the casing.

Accordingly, the anchor unit may be automatically se in response to application of string internal fluid ypressure to theactuator, as for example a conical body, no special landing equipment being required. The hydraulic cone, working in combination with the slips, which typically have directional teeth, allows the anchor assembly to adjust and move down the hole, under dynamic working load application, at a fraction of the loading required to move the unit up the hole. In this regard, some resistance to down-the-hole movement or adjustment of the anchor unit is desired since without such resistance the unit could move too far down the hole leading to build-up of excessive tension in the string. Further, the deeper the anchor unit is installed in the-well, the greater the hydraulic loading exerted on the actuator piston to set the slips for anchoring the unit; this result trends in the right direction, since the deeper the Well the greater the pump load reversal applied to the string requiring greater holding power for holding the tubing anchored. In'shallow wells, less holding power is desirable in order to allow the tubing to adjust correctly. Still further, because the conical actuator can yield up relative to the slips, displacing actuating iluid back into the tubing, the anchor can be dragged from the well starting from a fully actuated condition.

Additional objects of the invention include the proyision of means including a check seal, to block escape of uid pressure application to the ractuator piston surface in order that the anchor may remain set regardless of the differential pressure between the tubing interior and the casing annulus; the provision of means including a pressure rupturable element carried by the actuator to unblock escape of uid pressure application to the piston surface, as well as the provision for increasing uid pressure application in the well to rupture said element; and the use of couplings of unusually effective and easily fabricated construction for yblocking and unblocking -relative vertical ydisplacement of the tubular mandrel and slip structure, as will be brought out.

In its broader method aspects, the invention involves the steps that include transmitting fluid pressure to drive an actuator downwardly thereby to effect connection of the string 'supported slip structure to a well bore, and reducing such pressure to release the slips. Other steps include storing strain energy in the string, suddenly refleasing stored strain energy to allow string upward displacement relative to the slip structure, lsaid upward dis# placement suddenly lifting the actuator thereby to free the slip structure for disconnection from the well bore. Typically, 'the strain energy storage is effected to de# velop longitudinal tension in the string, and the'release of such tension is effected in response to shearing of a shear connection or rotation of the tensioned string;

These and other objects and advantages of the invention,"as well as the details of an illustrative embodiment, will be more fully understood from the following detailed description of the drawings, in which:

, FIG. 1 is a vertical elevationshowing the anchor unit tion of Vthe anchor unit after 'strain energy release to effect release of the slip structure;

FIG. 5 is a horizontal section taken on line 5 5 of FIG. 2;

FIG. 6 is a horizontal section taken on line 6-*6 of FIG. 2; A

FIG. 7 is a horizontal section taken on line 7 7 of FIG. 4;

FIG. 8 is an axially exploded and perspective illustration of the FIGS. 2-4 coupling parts;

FIG. 9 is a vertical half section showing a modified form of anchor unit embodying the invention;

FIG. 10 is a section taken on line 10-10 of FIG. 9;

FIG. 1l is a vertical section showing a still further 'modified 4form of anchor unit; and FIG. 12 is a section taken on lines 12-12 of FIG. l1;

FIG. 13 is a fragmentary vertical section showing a modified anchor unit actuator;

FIG. 14 is a fragmentary vertical elevation showing Well head equipment usable with the anchor unit actuator of FIG. 13;

FIG. 15 is a horizontal section similar to FIG. 6, `but showing a modified coupling construction; and

FIG. 16 is a fragmentary vertical section taken on line 16--16 of FIG. 15. In FIG. 1 a well tubing string is seen at 10 within a well 11 cased at 12. A vertically reciprocable pump 13 Ais located above the tubing inlet structure 14 for receiving production fluid such as petroleum. The string carries slip structure 15, typically embodied in an anchor unit 16 for connecting to the well bore such as `bore 17 of the casing. A pump rod 75 projects at the surface above the upper terminal of the string supported at 110.

It will be understood that the tubing is subject to lengthwise expansion and contraction in the well, in response to dynamic forces imposed during the pumping cycle and also in response to temperature fluctuations, thereby varying the tubing tension when it is anchored `by unit 16 deep in the well. The slips 15, when engaged with bore 17, resists upward movement of the string at the anchor unit location, but allow downward displacement of the anchor unit relative to the bore, with the limitation that such downward displacement is resisted by the slips.

Extending the description to FIG. 2, a tubular means connectible in upright series relation with the tubing string 10 for passing well fluid may include the tubular mandrel 21 having a pin end 22 coupled to the tubing as by collar 24. The slips 15 are seen to be circularly spaced about and carried on the mandrel 21, with wickers 2S facing outwardly toward the casing bore. A pump or sucker rod 75 passe's downwardly through the mandrel. One form of means to actuate the slips to connect to the well bore includes an actuator carried by the tubular means outwardly of the mandrel 21. A typical actuator is seen at 26 as being tubular and mounted on the mandrel and collar at 27 and 28 for axial movement relative thereto after shearing of pin connection 40 holding the actuator in up position. The actuator has a piston surface 29 communicable, a's through mandrel side port 30, with the interior of the mandrel 21 to receive application of well fluid pressure for transmitting force urging the slip structureoutwardly toward the casing. Such pressure is typically developed by the hydrostatic head of the column of uid lifted in the tubing by the pump 13. In this regard, the actuator and slips have wedge surfaces 31 and 32 therein and angled to urge the slips outwardly, as

, seen in FIG. 3, in response to downward movement of CII the actuator relative to the mandrel 21 and toward a sleeve 33, with which the slips have T-connection at 34, actuator surface 31 being conical. Flat spring fingers 35 carried -by the sleeve engage the outer slides of the slips to retract them inwardly in the absence of outward urging by the actuator. Annular seals are provided at 136 and 137 to seal off `between the actuator and collar, and between the'actuator and mandrel, preventing'escape of uid pressure exerted on piston surface 29.

Other'me'ans is 'also' provided to transmitstring loading exerted axially upwardly between the tubular means such as mandrel 21 and the slip structure, said other means typically having the functions of controllably blocking and unblocking release of strain energy stored in the string. Typically included within such other means is a coupling at the outside of the mandrel 21 and having load transmitting partsvlocated to initially block upward displacement of the mandrel 21 relative to the slip structure and to unblock such relative upward displacement in response to relative rotation of the mandrel and slip structure. As seen in the drawings, one coupling part functioning as described comprises a tubular clutch 36 made integral with the sleeve 33 'as by weld 37, and other coupling parts comprise lugs 38 integral with the mandrel and engaging the clutch to transmit string imposed loading thereto and in an upward direction. The clutch is tubular to pass the mandrel therethrough, and the lugs 38 stand out from the mandrel in order to engage the segmental and downward facing rim surfaces 39 of the clutch. Lower portions of the clutch 36 and upper portions 71 of the lugs 38 are located to block rotation of the mandrel 21 relative to the sleeve 33 and in the direction opposite to that indicated by arrow 43 in FIG. 4.

The clutch also has cutouts 41 sized to receive the lugs 38, and terminating upwardly at stepped surfaces 42 offset vertically and annularly staggered relative to clutch step surfaces 39. The function of cutouts 41 is to receive relative upward displacement of lugs 38 when they drop upwardly therein after predetermined rotation of the mandrel in the direction of arrow 43 in FIG. 4. Such mandrel rotation relative to sleeve 33 suddenly frees the lugs from engagement with clutch surfaces 39 and allows the lugs and the mandrel to suddenly move or rebound upwardly relative to the sleeve with consequent release of substantial strain energy stored in the vertically tensioned string. Prior to such rotation, sufficient torque must beapplied to the string 10, as by surface tongs 20, to shear the releasable connection or pin 44 between the sleeve 33 and mandrel 21. Accordingly, pin 44 prevents inadvertent release of the anchor unit, the slip wickers 2S engaging the casing bore 17 to resist rotation of the sleeve 33.

When the lugs have moved upwardly into the cutouts 41 a predetermined amount, a downwardly presented shoulder 50 of the actuator 26 intercepts upward displacement of upwardly presented mandrel shoulder 51 in order to develop upward force of impact to lift the actuator and free the slip structure for disconnection from the casing. As shown in FIGS. 2-4, mandrel shoulder 51 is annular, and shoulder 50 on the actuator 26 is also annular. When these shoulders engage, the actuator 26 is lifted relatively away from the slips, whereby they then are effectively free from force urging them outwardly toward the casing. Upward travel of the mandrel may also result in upward lifting of the relieved slips, as by engagement of shoulders 52 and 53 on the mandrel and slips respectively, as seen in FIG. 4. As a result, the slips are completely freed of connection to the casing or well bore.

The method of operation contemplated by the invention includes the steps of transmitting fluid pressure to drive an actuator downwardly for actuating the slip structure to connect to a well bore, storing strain energy in the string, suddenly releasing said strain energy to allow string upward displacement relative to the slip structure, and coupling said upward displacement to the actuator to elevate the actuator thereby to free the slip structure for disconnection from the well bore. Typically, the fluid pressure for actuating the slips is derived from application of string fluid pressure, and release of strain energy in the string is effected in response to sudden unblocking of string upward displacement tending to relieve strain in the string. As pointed out above in the described embodiment, the unblocking of string displacement may be carried out by applying sufficient torque to a tensioned string from rotating it to a condition where tension may be suddenly relieved.

Referring now to FIG. 9, the anchor assembly there shown in half section includes tubular mandrel 60, and a tubular and frusto conical actuator 61 carried on the mandrel for vertical axial movement against imposed resistance tending to hold the actuator in up-position. The actuator has a piston surface 63 communicating as through mandrel side port 64 with the interior of the mandrel to receive application of well iiuid pressure fortransmitting force urging the actuator downwardly, thereby displacing slips 65 outwardly toward the casing.

The actuator 61 and slips 65 have interengaged wedge surfacesv tapering downwardly at 66 and'67 respectively, and the slips have T-connection at 70 to a sleeve 68 carried on the mandrel, the latter having a central axis 69. Annular seals yare provided at 71 and 72 to seal off between the actuator and mandrel, preventing escape of liuid pressure exerted downwardlyon surface 63.

Sleeve 68 may be considered as included by the above referred to other means for transmitting string loading exerted axially upwardly between the tubular mandrel 60 yand the slip structure, said other means also functioning to block and unblock release vof strain energy stored in the string. Also typically included within said other means is a coupling at the ouside of the mandrel and having load transmitting parts located to initially block upward displacement of the mandrel relative to the slip structure and to unblock said relative upward displacement in respense to predetermined loading `application to the mandrel.

As seen in FIG. 9, one nof* the parts comprises a shear 'ring or flange 74,` and other parts are located to transmit mandrel downward loading to the sleeve independently ofthe shear ring, and to transmit mandrel upward loading to` the sleeve via the shear ring. Said other parts may typically include a nut 175 having thread mounting to the sleeve at` 76, and a compression ring 77 clamped axially between 'a' nut internal and upwardly facing shoulder 78 and the shear ring. Shear ring 74 is clamped betweenlthe compression ring and a sleeve internal and downwardly 'facing shoulder 79, and also extends at 80 outwardly of the mandrel and compression ring 77. The latter ring is carriedV on the mandrel in order to shear the ring 74 when the mandrelv is tensioned upwardly to sufficient extent. Downward loading istransmitted in compression fr'om the mandrel 60 to ring 77 and then to the nut shoulder 78. This feature prevents accidental shearing of ring 74 in case the pump rods arevdroppedin the tubing string. Finally, the mandrel and actuator have axially spaced shoulders 82 and 83 located inwardly of an annular locus defined by the slips to position the mandrel shoulder 82 for Vengaging and lifting the actuator after shearing of the ring 74 and upward travel of the mandrel following sufficient -upward tensioning thereof. As this ope-ration occurs, fluidin the chamber directly above actuator piston shoulder 63 is driven back through port 64 into the interior of the mandrel, and the slips are freed for discon-4 nection from the casing. The slips have dove-tail connection at 81 to the conical actuator 61, whereby after shearing of ring 74 the sleeve 68 and nut 175 are supported by the actuator 61 via the slips suspended therefrom.

It will also be noted that the apparatus of FIG. 9, for

example, may be normally operated to disconnect from the well casing without shearing of ring 74. Thus, assuming the conical actuator 61 has been displaced downwardly to drive the slips 65 outwardly in response to transmission of elevated fluid pressure through port 64 to piston surface 63, it is frequently possible to effect disconnection of the slips from the casing by sufficient lowering (as -by reduced pumping) of the fluid pressure transmitted to the surface 63 and by simultaneously exerting upward loading or pulling on the string including the mandrel 60, such upward loading being less than that required to shear ring 74. Thus, under-these circumstances, the sleeve 68 may be considered as integral with the mandrel. Accordingly, the combination of lowered fluid pressure plus upward loading exerted on the mandrel will accomplish the desired disconnection. Note in this regard, the angularity of the slip wickers, the upper faces 94 of which have greater angularity from vertical than the lower faces 95, a relationship facilitating desired connection and disconnection to and from the casing bore, in the manner described above.

Ring 74 may be dimensioned to transmit sufiicient upward loading, without shearing, to permit dragging of the anchor assembly out of the hole during an emergency even though the internal fiuid pressure transmitted to actuator surface 63 is not lowered. Upward dragging of the anchor assembly would then be resisted by engagement of the slip wickers with the casing; however, the fact that the actuator is hydraulically actuated permits it to yield upwardly relative to the mandrel when the upward force developed by slip wicker engagement with the casing in turn develops sufficient inwardly directed force components to in turn de-velop sufficient upward force transmission to the actuator 61, whereby the slips will then tend to release from engagement with the casing in view of the slip wicker design. Note also that the area of actuator piston surface 63 is sied so that the downward pressure developed does not exceed the drag-out force required to drag the fully actuated assembly out of the hole during an emergency. In this regard, shearing of ring 74 could -be resorted to as a final means of pulling the assembly out of the hole, i.e. if the above described drag-out operations with or without fluid pressure lowering were unsuccessful.

Finally, it is pointed out that during lowering ofthe assembly in the well, the mandrel 60V acts via the sleeve 68 to pull the slips 65 downwardly and relatively off the conical surface 66 of the actuator, tending to retract the slips inwardly, even though fluid Ipressure applied to the actuator urges the actuator toward the slips to spread them. As a result, force developed by wicker engagelment with the casing to oppose movement of the assembly down the hole (as may be supplied by vertical pumping of the well) is much less than force developed by wicker engagement with the casing to oppose movement of the assembly up the hole. This advantageous functioning or mode of operation is substantially different from that as seen in U.S. Paent 3,011,558 to Conrad, since when his cone faces down, the fluid ypressure for anchoring the slips is derived from the annulus and the actuated slips wickers prevent downward move-ment of the anchor in the well; on the other hand, when his cone faces up, the wickers prevent upward movement of the tool in the well.

The modified tubing anchor assembly seen in FIGS. 11 and 12 has the same structure as the assembly of FIG. 9, and accordingly the corresponding parts bear the same numerals. In addition, the FIGS. 11 and 12 assembly includes what may be characterized as spring means carried outside the mandrel to urge the actuator upwardly for aiding or assisting positive release of the slip structure 65 in response to sufficient lowering (as by reduced pumping) of well fluid pressure application to the actuator, as by transmission to surface 63. In the illustrated example of an unusually advantageous form of the spring 7 means, multiple compression springs 110 are provided to extend generally vertically between the sleeve 68 and actuator 61; also, the springs are located in the space between the circularly spaced slips, as indicated.

More specifically, the upper portions 111 of the springs 110 are received in guide bores 112 formed in the actuator, whereas lower portions 113 of the springs are extended in guide bores 114 of the sleeve 68. A key 115 interlocks the sleeve `68 and mandrel to block relative rotation thereof, thereby keeping the sleeve bores 114 in vertical alignment with the actuator bores 112. Further, the actuator and sleeve are kept in approximate vertical alignment by the T-connection interlocking at 70 and the dovetail connection at 81.

Referring now to FIG. 13, the modified assembly there shown includes a tubular mandrel 160, and a tubular and frustoconical actuator 161 carried on the mandrel for downward axial movement against imposed resistance tending to hold the actuator in up-position. The actuator has a piston surface 163 communicating as through clearance 263 and mandrel side port 164 with the interior 264 of the mandrel to receive application of we-ll fluid pressure for transmitting force urging the actuator downwardly, thereby displacing slips 165 outwardly toward the casing. So far, the actuator functioning is like that described in connection with FIGS. 4 and 9.

In accordance with this form of the invention, means is provided to block escape of fluid pressure application to the piston surface 163. Need for such a means occurs in high fluid level wells or where the fluid level falls and rises in the annulus 166, where insufficient pressure differential is created or maintained across the actuator to cause the anchor to properly set and grip the casing wall initially; or the anchor may set initially and then release when the fluid rises in the annulus.

In FIG. 13 the mentioned pressure release blocking means is in the form of a check or one-way seal, and specifically an annular elastomeric seal 167 having a U- shaped cross section. One flange 168 of the seal wipes the outer wall of the mandrel 160, and the seal operates to allow fluid pressure to pass through port 164 and up the clearance 263 past the seal to `gain access to the piston surface 163; however, the seal also blocks or traps the fluid at surface 163 against escape. By so blocking the applied pressure, the anchor remains set, regardless of the dierential pressure lbetween the tubing interior and the casing annulus. Further, the anchor tends to move down the hole and remain set, maintaining the tubing in stretched condition even after the fluid pressure in the tubing diminishes, since the maximum pressure is retained on the piston surface 163. Tubing stretch is of advantage in high angle holes where tubing goes down the hole only with difficulty. A check valve may also be substituted for the seal. O-ring seals 171 fand 172 correspond to similar iseals 71 and 72 in FIG. 9.

FIG. 13 also illustrates the provision of means to controllably unblock escape of fluid pressure application to the piston surface. It typically includes a pressure rupturable element such as disc 180 one side lof which communicates at 181 with blocked pressure in clearance 263. A retainer 182 threaded into the actuator holds the disc in place, and has a port 183 communicating with the annulus at the opposite side of the disc. A pressure seal 186 is provided at the clearance side of the disc. FIG. 14 shows the provision of a valve 187 `at the well head to control the upward flow of production fluid in the tubing string 10. The valve may be closed and the pump 13 operated to increase the tubing internal pressure sufficiently to rupture the seal 186 and disc 180, and thereby reduce the downward pressure (or equalize the pressure) acting on the actuator 161, raiding release of the slips. Further, the opening of valve 187 can be increased without regard to pressure in the tubing, lsince diminishing thereof does not diminish the pressure on piston face 163, in view of the operation of seal 167.

. Referring now to FIGS. 15 and 16, an advantageously simple coupling construction is illustrated, the functioning of the coupling being generally similar to that of the coupling seen in FIGS. 2 and 8. The mandrel 210 has peripheral segment recesses 211 and bounded by vertically spaced horizontal shoulders 212 and 213. Lugs in the form of annular segments 214 are fitted in the recesses and connected thereto `by vertical welds 215. Thus, the lugs and mandrel may 'be separately machined, rather than formed integrally.

The lugs fbear upwardly against downward facing segmental rim ysurfaces 216 of clutch sleeve 217. The latter has cut-outs 218 sized to receive the lugs when they drop upwardly therein after predetermined rotation of the mandrel, as similarly described in connection with FIG. 4. A nut 219 is connected to the clutch sleeve and houses the coupling structure. Sleeve 217 corresponds to sleeve 33 in FIG. 2.

Iclaim:

1. In a well tubing anchor assembly, tubular body means connectible in upright series relation with a tubing string for passing Well fluid, second means including slip structure and an actuator carried by said tubular means, the actuator carried for vertical movement relative to said tubular means and having a piston surface communicable with the interior of said tubular means to receive application of well fluid pressure for urging the actuator downwardly thereby displacing the slip structure toward the well casing in order to anchor the string against upward movement relative to the casing, other means for transmitting between said tubular means and slip structure loading exerted upwardly by the string, said tubular means and other means including a coupling for blocking relative vertical displacement of the tubular means and slip structure and for unblocking said relative vertical displacement upon coupling releasing loading application to the tubular means, upward displacement of the tubular means relative to the slip structure then being operable to urge the actuator upwardly out of said slip displacing relation, and means to block escape of fluid pressure application to said piston surface.

2. The combination as defined in claim 1 in which said last named means comprises a fluid check valve.

3. The combination as defined in claim 2 in which said actuator and tubular body means form a clearance for passage of said well fluid pressure application to the piston surface, and said fluid check valve comprises a seal carried at the clearance to pass said fluid pressure application in one direction but to block escape thereof in the opposite direction in said clearance.

4. The combination as defined in claim 1 including means to controllably unblock escape of fluid pressure application to the piston surface.

5. The combination as defined in claim 4 in which said last named means includes a pressure -rupturable element carried by the actuator and including means to increase fluid pressure application in the well to rupture said element.

6. In a well tubing anchor assembly, tubular body means connectible in upright series relation with a tubing string for passing well fluid, second means including slip structure and an actuator carried by said tubular means, the actuator carried for vertical movement relative to said tubular means and having a piston surface communicable with the interior of said tubular means to receive application of well fluid pressure for urging the actuator downwardly thereby displacing the slip structure toward the well casing in order to anchor the string against upward movement relative to the casing, said tubular means including a mandrel and a string carried on the mandrel to support the slip structure, a clutch on the sleeve, and a lug integral with the mandrel and engaging the clutch below the actuator, the clutch and lug blocking relative vertical displacement of the tubular means and slip structure and unblocking said relative vertical displacement upon predetermined rotary loading application to the tubular means, upward displacement of the tubular means relative to the slip structure then being operable to urge the actuator upwardly out of said slip ydisplacing relation.

7. In a well tubing anchor assembly, rotary tubular means including an axially extending mandrel connectible in upright series relation with a tubing string for passing well fluid, second means including slip structure and an actuator carried by said tubular means outwardly of the mandrel, the actuator carried for vertical movement relative to said mandrel and having a piston surface communicable with the interior of said tubular means to receive application of well fluid pressure for urging the actuator downwardly thereby displacing the slip structure toward the well casing in order to anchor the string against upward movement relative to the casing, a sleeve carried on the mandrel to support said slip structure, a clutch integral with the sleeve and a lug integral with the mandrel and engaging the clutch, said clutch and lug blocking upward displacement of t-he mandrel relative to Athe slip structure and unblocking said relative upward displacement in response to predetermined rotary loading application to the mandrel, said actuator being located to receive upward force application transmitted by the mandrel in response to said unblocked relative upward displacement thereof for lifting the actuator out of said slip displacing relation.

8. The well tubing anchor assembly of claim 7 including a shear-able release connection between the sleeve and mandrel and sized to shear of and unblock the mandrel for rotation relative to the sleeve upon applica- -tion thereto of sufficient torque transmitted by the mandrel in one direction about the axis thereof.

9. The well tubing anchor assembly of claim 8 in which portions of the clutch and lug are located to block rotation of the mandrel relative to the sleeve and in the opposite direction about the mandrel axis.

10. The well tubing anchor of claim 8 in which the clutch has a step shoulder which engages the lug to block relative upward displacement of the mandrel, said second means having a shoulder located to intercept upward displa-cement of the mandrel following shearing olf of said release connection and suicient rotation of the lug to step olf said step shoulder.

11. The well tubing anchor of claim 7 in which said slip structure includes multiple slips spaced about the mandrel and supported by said sleeve, the actuator and slips having wedge surfaces angled to urge the slips outwardly in response to downward movement of the actuator relatively toward said sleeve.

12. The well tubing anchor of claim 11 in which the mandrel and actuator have axially spaced shoulders located inwardly of an annular locus defined by said slips to position the mandrel shoulder for engaging and lifting the actuator.

13. The combination as defined in claim 7 in which the mandrel has a peripheral recess receiving the lug between vertically spaced mandrel shoulders.

14. In a well tubing anchor assembly, rotary tubular means including an axially extending mandrel connectible in upright series relation with a tubing string for passing well lluid, second means including slip structure and an actuator carried by said tubular means outwardly of the mandrel, the actuator carried for vertical movement relative to said mandrel and -having a piston surface communicable with the interior of said tubular means to receive application of well fluid pressure for urging the actuator downwardly thereby displacing the slip structure toward the well casing in order to anchor the string against upward movement relative to the casing, a sleeve carried on the mandrel to support said slip structure, load transmitting parts including a shear ring extending about the mandrel, others of said parts being located to tnansmit mandrel downward loading to the sleeve independently of the shear ring and to transmit mandrel upward loading to the sleeve via the s-hear ring, said ring initially blocking upward displacement of the mandrel relative to the slip structure and unblocking said relative upward displacement in response to predetermined upward loading application to the mandrel acting to shear the ring, said actuator being located to receive upward force application transmitted by the mandrel in response to said unblocked relative upward displacement of the mandrel for lifting the actuator out of said slip displacing relation.

15. The well tubing anchor assembly of claim 14 wherein said other parts include an annular nut having thread mounting to the sleeve, and a compression ring clamped axially between a nut internal and upwardly facing shoulder and said shear ring, the shear ring being held clamped in position by said compression ring and a sleeve internal and downwardly facing shoulder and also extending outwardly of the mandrel.

16. In combination, a well tubing string including a mandrel, anchor means on the string including slips and actuator means movable leng-thwise of the mandrel to actuate the slips to connect to a well bore, and a rotary release connection between the mandrel and said anchor means and having a lirst rotary position in which upward displacement of the mandrel relative to the slips is blocked so that the string may be upwardly tensioned, the connection having a second rotary position in which the mandrel is rotated relative to the slips so as to be movable upwardly relative to the slips for releasing string tension to effect upward impact of said anchor means for releasing the slips from connection to the well bore.

17. The method of operating tubing string supported slip structure in a well, that includes transmitting iluid pressure to drive an actuator downwardly for actuating the slip structure to connect to a well bore, storing strain energy in the string by tensioning the string above the slip structure w-hile holding the string against upward displacement proximate the slip structure, rotating the string to thereby effect sudden release of said strain energy allowing string upward displacement relative to the slip structure, and coupling said upwardly moving string to the actuator with impact to elevate the actuator thereby to free the slip structure for disconnection from the well bore.

18. The method of operating tubing string supported slip structure in a well, that includes transmitting iluid pressure to drive an actuator downwardly for actuating the slip structure to connect to a well bore, storing strain energy in the string by tensioning the string above the slip structure while holding the string against upward displacement proximate the slip structure, rotating the string to thereby effect sudden release of said strain energy allowing string upward displacement relative to the slip structure, and coupling said upward displacement to the actuator to elevate the actuator thereby to free the slip structure for disconnection from the well bore, said release of strain energy being effected in response to sudden unblocking of string upward displacement tending to relieve strain in the string.

19. The method of operating tubing string supported slip structure in a well, that includes applying lluid pressure in said tubing to drive an actuator downwardly to effect connection of the slip structure to a well bore, storing strain energy in the string by tensioning the string above the slip structure while holding the string against upward displacement proximate the slip structure, and rotating the string to thereby effect sudden release of said strain energy allowing string upward displacement relative to the slip structure, and coupling said upward displacement tothe actuator to elevate the actuator thereby to free the slip structure for disconnection from the well bore.

20. The method of anchoring and releasing a tubing `string in a well, the string supporting slip structure, that includes applying force to drive an actuator downwardly to effect connection of the slip structure to a well bore, maintaining said connection during lengthwise tensioning of the string above t-he slip structure while holding the string against upward displacement proximate the slip structure for storing strain energy therein, rotating the string to thereby effect sudden release of said strain energy allowing string upward displacement relative to the slip structure, and coupling said upward displacement to the actuator to elevate the actuator thereby to free the slip structure for disconnection from the well bore.

2,735,497 2/1956 Brumleu et al. 166-212 2,815,080 12/1957 Long 166-120 2,874,784 2/1959 IvBaker' 166-212 2,982,358" "4/1961 lrowri'..."I 166-120 3,002,564 10/1961 Baker 166-212 3,011,557 AV12/1961 d Conrad 166-212 12/1961 Conrad 166-212 JAMES A. LEPPINK, Primary Examiner. 

